1. Field of the Invention
Present example embodiments of the technology described herein relate to an input data processing program and an information processing apparatus for processing data inputted from an input device such as a touch pad.
2. Description of the Background Art
Conventionally, known is a technology for allowing an operator to touch-operate a pointing device such as a touch panel with a finger and the like so as to control an object (for example, a cursor) and the like displayed on a screen. Here, an input position on an input surface may be determined based on an area on which the finger touches the input surface. For example, in FIG. 18, an operator touches an input surface 91 on a circular area 92 with a finger. At this time, the input position is determined as a position 93 representing the center of the circular area 92. That is, it is determined that the operator is designating the position 93 representing the center of the circular area 92. As a method for determining the input position based on the touch area, a method for determining the centroid of the touch area as the input position, can be used.
However, an area on which the operator touches the input surface with the finger may be variable. Therefore, in the aforementioned method for determining the input position based on the touch area, the input position may move against the operator's intention, resulting in an operation unintended by the operator being performed. Particularly, when the operator starts to touch the input surface with a finger or when the operator stops touching the input surface (when the operator removes the finger from the input surface), a position and a size of the finger touch area may substantially change. Therefore, especially at the touch start point or at the touch stop point, the operation unintended by the operator is likely to be performed.
FIG. 19 is a diagram illustrating a state of an input surface in which an operator is removing a finger from the input surface in the state shown in FIG. 18. That is, at the time shown in FIG. 19, the operator is touching the input surface 91 on a circular area 94 with the finger. At this time, the input position is determined as a position 95 representing the center of the circular area 94. Accordingly, when the state shown in FIG. 18 changes to the state shown in FIG. 19, it is determined that the input position moves from the position 93 to the position 95. However, in this case, the operator simply desires to remove the finger from the input surface with no intention to move the input position. That is, in this case, an operation unintended (or undesired) by the operator, such as moving a cursor on a screen, is performed due to the input position being moved. Therefore, the operator feels that the controllability of a pointing device is unsatisfactory. Further, not only when the operator removes the finger from the input surface but also when the operator attempts to touch the input surface with the finger or to move the finger on the input surface, the change of the touch area may cause the operation unintended by the operator.
A touch operation position detection apparatus disclosed in Japanese Laid-Open Patent Publication No. 2003-5913 (hereinafter, referred to as Patent Document 1) has light emitting elements and light receiving elements disposed around a touch panel, and a camera positioned lateral to the light receiving elements. The touch operation position detection apparatus calculates, based on information from the light receiving elements, the center position of an area on which the operator touches with a finger, and corrects the center position based on photograph information from the camera. Thus, the touch operation position detection apparatus is directed to accurately calculate an input position as intended by the operator.
In the touch operation position detection apparatus disclosed in Patent Document 1, it is necessary to dispose the light emitting elements and the light receiving elements around the touch panel, and further provide the camera. Therefore, the technology disclosed in Patent Document 1 causes an increase in cost and size of the apparatus, and requires the apparatus of complicated structure. Further, reduction in the numbers of the light emitting elements and the light receiving elements causes a deterioration of a detection accuracy, whereby it is impossible to accurately correct the center position at any time. When the center position cannot be accurately corrected, the operation unintended by the operator will be performed as described above, thereby deteriorating controllability of the pointing device.